Squeegee roller arrangement

ABSTRACT

In an arrangement of a vertical pair of rollers for transporting a sheet therebetween while applying a liquid to the lower surface of the sheet, providing the ends of the lower roller with a concave configuration to prevent wetting the upper roller and the upper surface of the sheet.

United States Patent Appl. No. Filed Patented Assignee SQUEEGEE ROLLERARRANGEMENT [56] References Cited UNITED STATES PATENTS 432,606 7/ 1890Dawson 1 18/250 1,494,094 5/1924 Allen I 18/250 X 2,203,250 6/ 1940Bolhotner et a1. 1 18/247 Primary Examiner-John P. McIntoshAttorneys-Walter O. Hodsdon and Robert L. Randall 4 claims 1 DrawingABSTRACT: In an arrangement of a vertical pair of rollers for US. Cl.118/249 transporting a sheet therebetween while applying a liquid toB05c 1/00 the lower surface of the sheet, providing the ends of thelower Field of Search 1 18/249. roller with a concave configuration toprevent wetting the 250. 247. 258. DIG. 15; 68/202 upper roller and theupper surface of the sheet.

""ZTJIIE f T J gfg PATENTEDSEPMIHYI 3,504 393 ANTHONY EARLE A TTORNEYSSQUEEGEE ROLLER ARRANGEMENT BACKGROUND OF THE INVENTION This inventionrelates to roller arrangements for apparatus such as photographicprocessing apparatus in which excess liquid applied to a sheet, web orfilm is removed by a pair of rollers in the roller arrangement.

One roller arrangement used in a photographic print processing apparatuscomprises a pair of similar rubber covered rollers respectively mountedfor rotation about horizontal axes, one roller being disposed verticallyabove the other, and the lower roller being partly immersed in a bath ofprocessing liquid. During operation the rollers are driven in oppositesenses to produce forward movement of a print being passed therebetween,and the lower roller acts as an applicator roller to apply processingliquid to the lower side of the print. Excess liquid squeezed from theprint as it enters the nip of the roller forms a liquid bead in front ofthe nip and may return to the bath. Under some conditions there is atendency for liquid from the bead to travel around the ends of the lowerroller and wet the upper roller. This may cause undesirable rewetting ofthe print, and it is an object of the present invention to provide aroller arrangement which reduces or obviates this tendency.

SUMMARY OF THE INVENTION According to the present invention, in a rollerarrangement for a photographic processing apparatus or other apparatusin which excess liquid is removed from a sheet, web or film by a pair ofrollers in the roller arrangement, the outer surface of the lower one ofthe pair of rollers is of substantially the same axial length as thecooperating surface of the other roller during operation, and the endsof the said lower roller are formed so that an acute angle is defined ateach peripheral edge between its outer surface and the adjacent portionof the end of the roller.

The cooperating surface of the lower roller is preferably slightlylonger rather than shorter than the cooperating surface of the upperroller.

The ends of the lower roller may be of dished form to produce thedesired sharp peripheral edge.

The rollers may be urged together by pressure which causes deformationof the end faces of the lower roller during operation.

The various features of novelty which characterize the present inventionare pointed out with particularity in the claims annexed to and forminga part of this specification. For a better understanding of theinvention, its operating advantages and the specific objects obtained byits use, reference should be had to the accompanying drawing anddescriptive matter in which a preferred embodiment of the presentinvention is illustrated and described.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawing, theroller arrangement comprises an upper roller 11 and a lower roller 12,both rollers preferably having a cylindrical outer surface provided by acoating of rubber, l3 and 14, or other deformable material, on a shaft,15 and 16. The shaft 16 of lower roller 12 is mounted horizontally inbearings in spaced vertically disposed support members 17 so that theouter surface can dip into processing liquid 18 contained in a trough19. The shaft 15 ofupper roller 11 is also carried by movable bearingsin the support members 17, and this roller is biased downwardly bysprings 20 into contact with the lower roller to form a substantiallyhorizontal nip therebetween.

The upper and lower rollers have cylindrical outer surfaces of similarradius and substantially identical length. When the rollers are pressedtogether for operation the lower roller may be as long as the upperroller or may be marginally greater in len th, say 0.01 inch longer.

e ends 21 of the lower roller 12 are concave so as to produce sharpperipheral edges 22 to the cylindrical outer surface of this roller. Forthis purpose the ends are concave and may be dished or, as shown,frustoconical in shape. In the latter case successful operation has beenobtained with an acute angle at the peripheral edge of from 65 to 70between the outer surface and each end face. The pressure between therollers produced by the springs 20 is preferably sufficient to deformthe lower roller 12 to form a lip 23 at its ends and reduce the acuteangle at the peripheral edge between the rollers. This deformation ofthe end faces of the lower roller tends to deflect away from the upperroller any liquid which is carried upwardly by the end faces of thelower roller.

In operation of the processing apparatus a sheet of photographic paperis passed between the rollers 11 and 12. The rollers rotate in oppositesenses with the sheet, and the lower roller applies liquid from thetrough to the underside of the sheet. Excess liquid is removed by therollers. Effective operation of the roller arrangement has been obtainedin practice with a decreased tendency for wetting of the top surface ofthe sheet.

Although the invention has been described in relation to a rollerarrangement having a lower roller which constitutes a liquid applicatorit should be appreciated that the invention is also applicable toarrangements where liquid is only removed from the sheet, web or film.

Thus, it will be seen that the present invention provides a novel rollerconstruction utilizing concave end surfaces whereby the upper roller isnot wet by liquids being transferred thereto by the end of the lowerroller. As a result, the possibility that a sheet or web beingtransported by the rollers will have the upper surface wetted is reducedor eliminated.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be un derstood thatvariations and modifications can be effected within the spirit and scopeof the invention.

We claim:

1. In a roller arrangement comprising a pair of substantiallyhorizontally disposed rollers, said rollers being longitudinally andaxially aligned with one roller above the other forming a substantiallyhorizontal nip therebetween, the lower roller being at least partiallyimmersed in a liquid and having a resilient peripheral surface, the endsof said lower roller having a concave configuration which is symmetricalabout the roller axis and which forms an acute angle between theperipheral surface and each end surface whereby liquid is nottransferred around the ends of the lower roller to wet the upper roller.

2. The invention according to claim 1 wherein the length of the lowerroller is at least equal to the length of the upper roller.

3. The invention according to claim 1 wherein the upper and the lowerrollers are urged together by a radial force whereby the end surfaces ofthe lower roller are deformed.

4. The invention according to claim 1 wherein the acute angle is between65 and 70.

1. In a roller arrangement comprising a pair of substantiallyhorizontally disposed rollers, said rollers being longitudinally andaxially aligned with one roller above the other forming a substantiallyhorizontal nip therebetween, the lower roller being at least partiallyimmersed in a liquid and having a resilient peripheral surface, the endsof said lower roller having a concave configuration which is symmetricalabout the roller axis and which forms an acute angle between theperipheral surface and each end surface whereby liquid is nottransferred around the ends of the lower roller to wet the upper roller.2. The invention according to claim 1 wherein the length of the lowerroller is at least equal to the length of the upper roller.
 3. Theinvention according to claim 1 wherein the upper and the lower rollersare urged together by a radial force whereby the end surfaces of thelower roller are deformed.
 4. The invention according to claim 1 whereinthe acute angle is between 65* and 70*.